1. Field of the Invention
The present invention relates to printing multiple-color copies in a single printing pass. More specifically, the present invention relates to a printing plate capable of producing high resolution, multiple-color copies in a single printing operation pass.
2. Related Art
Currently, printing in multiple colors requires a separate stencil for each color which is produced manually or by a photoetching process. A stencil is a thin sheet or plate in which a pattern of cut-outs or openings are treated to allow an applied pigment to pass through, bounded by the edges of the openings, thereby allowing the pigment to penetrate to a surface beneath.
It should be noted that the term "pigment" is used hereinbelow to indicate paint, ink, crayons, etc. and encompasses the use of some form of pigment in a carrier or pigment in a carrier vehicle.
After a separate stencil is formed for each desired color, a first stencil is placed on the printing machine wherein fluid pigment of a single desired color is applied and a squeegee is dragged across both the stencil and the pigment. As only one color may be applied per pass of the squeegee and per stencil, the first stencil must be replaced with a second stencil and a second pass of the squeegee is required to print the second color. As a result, high volume printing operations have utilized massive printing machines having multiple printing heads, with each printing head being responsible for applying one color. These machines operate by having either the printing heads revolve around the work pieces, or the work pieces revolve around the multiple printing heads.
Certain disadvantages associated with the conventional method of screen printing include that multiple color screen printing currently requires multiple etched stencils accomplished generally by a photoetching or a manual process. The photoetching process requires additional expense both in terms of equipment and in labor.
The conventional printing process also requires the use of pigment which is in fluid form on a stencil. This is disadvantageous in that it often results in pigment which escapes the confines of the screen printing stencil, resulting in additional expense with respect to loss of pigment and additional cleanup costs.
The current printing process also carries the disadvantage of requiring the pigment supply to be applied nearly simultaneously with the printing operation, increasing the complexity of the printing operation and attendant concerns.
A further disadvantage of the existing state of technology is that no screen printing operation currently provides for high resolution multiple-color copies in a single printing pass.
Accordingly, the foregoing disadvantages greatly limit the public's ability to enjoy multiple color copies by practical barriers relating to space, cost, and cleanup.